JP2000516714A - Magnetic current sensor - Google Patents

Abstract

(57) Abstract: A current determiner having an output representing an input current, supported on a substrate and electrically isolated from each other, but a magnetic field generated around an input conductor by any input current A current determinator including an input conductor for input current and a current sensor having a sensor located therein. The sensor extends along the substrate in a direction generally perpendicular to the extension of the input conductor and is formed of at least one pair of thin-film ferromagnetic layers separated by a non-magnetic conductive layer. The sensor can be electrically connected to electronic circuits formed in the substrate, including the non-linear adaptive circuit, to provide an input current indication that increases accuracy despite the non-linearities in the current sensor. The sensor may further include a current sensor in the bridge circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION                                Magnetic current sensor                                Background of the Invention   The present invention relates to a ferromagnetic thin film structure exhibiting relatively large magnetoresistance characteristics. In particular, It relates to such a structure used to sense a magnetic field.   Many types of electronic systems are digital systems such as memories and field sensors Utilizes magnetic devices including both analog systems. Magnetometer and others Magnetic sensing devices are available in various types of magnetic disk memory and magnetic tape storage systems. It is widely used in many types of systems, including systems. Such devices are: Provide output signals that are representative of the magnetic field sensed by these devices under various circumstances You.   One application of such a magnetic field sensor is to be generated by current in a conductor The magnetic field is used as a basis for inferring the nature of such currents that produce these fields. It may be sensed. This is a magnetic field created by a large current for a long time For smaller current ranges, including relatively small currents. It is more difficult to realize such sensing. For example, create a field to be measured Electric current simply transmits signal information, not to conduct large electrical energy. In situations where it is supplied as a basis for You need to know.   Such a situation is a problem for many medical, instrument, and control systems. Occurs in In these systems, each part of the system comes from an external source, Or the need to send signals from other parts of the system through signal interconnects I will. Often, conductors carrying signal currents for such purposes are obtained. Part of the system that includes a sensor configuration for these signals to measure the magnetic field Must be electrically insulated from the One example is the signal in the loop current The long current loop that carries the information is grounded by lightning or electrostatic discharge. Resulting in a large voltage potential. Such potentials are often Signal sensing and receiving circuitry. This is because the circuit is still Circuit must be able to capture the signal information contained in the loop current. Needed to avoid damage to.   Signal isolators for such purposes are often cost, convenience and And preferably on a monolithic integrated circuit chip for reasons of system performance Is done. In such an arrangement, the magnetic field provided by the current containing the signal is detected. To this end, one or more solid-state magnetic field sensors are used. Used in this situation One type of magnetic field sensor is a Hall effect device. Such a device Sensitive to magnetic fields due to small currents due to the limited sensitivity of the device to magnetic fields Often it is not satisfactory.   Furthermore, the configuration for improving the limited sensitivity of the Hall effect device is satisfactory. Often there is no significant improvement or replenishment measure. Where to use the field concentrator In such cases, it is difficult to deploy in a monolithic integrated circuit including a Hall device. what Therefore, the magnetically sensitive axis of the device is monolithic The Hall device in the integrated circuit is perpendicular to the direction extending across the substrate supporting the device. I.e., the sensitivity axis of the device is the thickness of the device, not its width or length. This is because it is parallel to the direction. It also relates to the magnetic field measured by the Hall device. The information provided by a hall device is in the form of a voltage, which Limit use in bridge circuits. If a bridge circuit is used, the current signal information The output signal providing the information can be increased.   Hybrid integrated circuit or monolithic integration for signal isolation Another possibility in any of the circuits is that the intensity of the electromagnetic radiation is The use of a light source controlled by the signal current. Such light sources are integrated To infer the nature of the signal current from the transmitted and received light deployed in the circuit It is electrically insulated from the photodetectors used. This is a variety of alternative capacity bases. When performing capacity based coupling solutions Unsatisfactory solution due to difficult nearing and economic problems . Thus, signal eyes that can be manufactured at a reasonably economical cost and exhibit relatively high sensitivity Sollation equipment is required.Summary of the Invention   The invention provides a display of an input current at an output with respect to an input current supplied from a source. Is provided. The current determiner includes an input conductor and a first current sensor. Which are supported on a substrate and are adjacent but electrically insulated from each other. Spaced such that the first current sensor originates from any input current. Placed in a magnetic field. The first current sensor is magnetoresistive, anisotropic and strong It is formed by a plurality of thin film layers that are magnetic. At least two of the thin film layers are They are separated from each other by a nonmagnetic conductive layer located therebetween.   The first current sensor extends primarily along a first direction across the substrate and includes The force conductor is primarily along a second direction across the substrate that is substantially orthogonal to the first direction. Extend. A layer made of a material having high magnetic permeability is formed between the input conductor and the first current sensor. Can be used with a magnetic field concentrator and And acts as a shield against any unwanted external magnetic fields.   This sensor can be electrically connected to other electronic circuits formed in the substrate. This For a circuit like this, the input current is May be included to more accurately display To increase sensitivity Another conductor adjacent to the input or output conductors to form a bridge circuit for A flow sensor may also be provided.                             BRIEF DESCRIPTION OF THE FIGURES   1A and 1B show a portion of a monolithic integrated circuit structure embodying the present invention. FIG.   2A, 2B, 2C and 2D are partial layer diagrams of the structural part shown in FIG. is there.   FIG. 3 shows the characteristics of the structure as shown in FIGS.   FIG. 4 is a schematic circuit diagram of a circuit for realizing the present invention.   FIG. 5 is a schematic circuit diagram of another circuit for realizing the present invention.   FIG. 6 shows a plan view of a portion of another monolithic integrated circuit structure embodying the present invention. You.Detailed Description of the Preferred Embodiment   Signal isolator based on magneto-resistive sensing of magnetic states occurring internally The magnetic field sensor for can be advantageously manufactured using a ferromagnetic thin film material. This Such devices are mounted on the surface of a monolithic integrated circuit, thereby providing a sensor device. A convenient electrical connection between the device and the arithmetic circuit therefor can be provided.   Recently, such sensors have been combined with two anisotropic ferromagnetic thin films. By providing it in the form of an intermediate thin layer of a separation material having a major surface, The thickness of the ferromagnetic thin film and intermediate layer of the "sandwich" structure is sufficiently small , It was found that a "giant magnetoresistance effect" could be obtained in the sensor . This effect is due to the fact that these ferromagnetic films and intermediate By forming such a sensor, formed can be enhanced. result The well-known anisotropic magnetoresistive response due to the "giant magnetoresistance effect" Producing a magnetoresistive response that can range up to a greater order of magnitude than when Can be. Sensing the magnetic field outside a monolithic integrated structure device containing such a sensor For known sensors similar to those described herein, see J.A. M. Daughton No. 08 / 384,647, `` Magnetoresistive S. tructure With Alloy Layer '' and J. M. Daughton's co-pending U.S. patent application number 08/096, No. 765 `` Magnetic Structure with Stratified Layers '' I have. In both applications, Assigned to the same assignee as the present application, Also in this specification Incorporated for reference.   FIG. Monolithic with support semiconductor chip as part of isolator substrate FIG. 2 is a plan view of a signal isolator formed as a part of the integrated circuit. Isole Data board It is convenient to provide an arithmetic circuit for this signal isolator inside. possible. Or The signal isolator is Hybrid collection on ceramic substrate It can be formed as part of an integrated circuit. FIG. 1B A part of the diagram shown in FIG. Sarana FIG. 3 is an enlarged partial view for clarity, Also cut out part for further clarification It exposes the structure below. Structure shown as used An optional protective layer deployed throughout, For clarity of some other layers It is omitted in the figure for In the same figure, the structural part located below the other structural part Is shown in dotted form, Other structural parts are shown in solid line form.   1A and 1B, FIG. 2A, FIG. 2B, FIG. 2C, 2D and 2 E is Layer diagram of the corresponding structural parts marked in FIGS. 1A and 1B It is. These layer diagrams are The structural layers leading to the structure shown in FIGS. 1A and 1B Shows, Not an exact cross section, Many dimensions exaggerated or reduced for clarity Have been.   As mentioned above, The current sensing structure Typically, Mounted on a semiconductor chip 10 , Semiconductor chips are Appropriate arithmetic circuits for the sensors are provided internally. Electrical The insulating layer 11 On the semiconductor chip 10 by sputtering deposition of silicon nitride Formed, A pair of ferromagnetic thin film layers separated from each other by a non-magnetic conductive intermediate layer Support current sensor "sandwich" structure with More on this later Details will be described. Of the current sensor formed by the semiconductor chip 10 and the support layer 11 The board for FIG. 2A, FIG. 2B, 2C and 2E, Reference number 10, 11 Indicated by In these figures, the insulating layer 11 and the semiconductor chip 10 are distinguished from each other. Not. In the higher resolution diagram of FIG. 2D, Only part of layer 11 is shown . Typically, Layer 11 is approximately 10 Formed to a thickness of 000mm You.   afterwards, The “sandwich” structure described above is provided on layer 11. Ferromagnetic thin film layer And each of the middle layers A magnetoresistive circuit resistor acting as a current sensor As a basis for forming Deployed by sputtering deposition. This multi-layer structure The structure is Has a sheet resistivity of about 13Ω / □ or more, Giant magnetism over 5% Resistance effect, And a saturation field of about 40 Oe.   In this structure, The first tier to be deployed is: Sputter deposited on nitride layer 11 Composite ferromagnetic thin film layer, As shown in FIG. 2D, The composite ferromagnetic thin film layer One stratum 12 is 65% nickel, 15% iron and 20 % Alloy with a thickness of 40%, This is typically about 10, Has a magnetic saturation induction of 000 gauss obtain. The deposition of this layer Becomes a film having a face-centered cubic structure, One parallel to the drawing plane This is done in the presence of an external magnetic field in the plane of the oriented film. At the time of this production Than, Access in the direction along the plane of the drawing is facilitated. Second Stratum 1 3 is also Provided in a sputtering deposition process in the presence of a similar manufacturing magnetic field . The second stratum is 15% thick with 5% iron and 95% cobalt Formed in As a result, this material About 16, Has a magnetic moment of 000 Gauss I can do it. this is, The value is higher than the magnetic moment of the first stratum 12. Materials with a high magnetic moment Deployed next to the next formed intermediate layer, Obtain a larger giant paramagnetic effect, The lower moment of stratum 12 is The resulting current sensor is Compared to the case without this, Higher for smaller places Deployed to maintain high sensitivity.   afterwards, The middle layer 14 Deployed by sputter deposition on layer 13 It is. This intermediate layer Conductive but non-magnetic. Layer 14 is Typically, 3 A 5 mm thick copper is formed. After the deployment of Tier 14, Second composite ferromagnetic on layer 14 A thin film layer is formed, To use the same deposition process, Its structure is Because the order is reversed outside is, It corresponds to the structure of the first composite layer comprising stratums 12 and 12. This As a result, The layer with the larger magnetic moment is again adjacent to layer 14, Small magnetic motor A layer having a segment is disposed thereon. Other than the above, these layers are the same Because In FIG. 2D, These correspond to stratums 13 and 12, 13 'And 12'.   After this "sandwich" structure is completed, 20 of tantalum or tantalum nitride A 0 ° layer is sputter deposited on the stratum 12 ′, This allows Lower stray To passivate and protect Tom 12 ' Electricity for circuit purposes Enable interconnectivity. The resulting layer of tantalum or tantalum nitride 15 is From its conductivity, Cause some shunting of current from the rest of the current sensor. Strain, From this, Giant magnetoresistance effect achieved by a structured current sensor Effectively reduce fruit. Layer 15 is Visible compared to ferromagnetic composite and non-magnetic interlayers Because it is so thick, In FIG. 2D, a part is omitted and illustrated.   Similarly, A further layer 16 deposited on layer 15 Relatively large thickness of 100mm Because In FIG. 2D, a part is omitted and illustrated. Layer 15 First sputtering Wash, Approximately 75 ° is removed. On the cleaned layer 15, 40% chromium and Layer 16 is sputter deposited as a 60% silicon chromium silicon layer, in addition Used as an etch stop when etching the provided milling mask layer later To use.   Therefore, Another layer of silicon nitride, Sputter deposits to a depth of 1000 mm on layer 16 Pile up, This is used as a milling mask, The remaining part of this layer Set up later Built into the additional insulation layer This layer is not shown in FIG. 2D. On this silicon nitride mask layer, After etching A mask on the silicon nitride mask layer. Like forming an etching mask to leave a mask pattern, Photoresist Is deposited and patterned. This last pattern is Milling through it After doing The result is a serpentine resistor structure You. This meandering resistor structure, Connect this resistor to the equipment circuit network. Acts as a current sensor having an interconnect extension extending therefrom for interconnecting I do. Reactive ion etching using patterned photoresist What The silicon nitride layer is formed up to the chromium silicon layer 16 acting as an etch stop. The exposed portion of the mask layer is removed. The rest of the silicon nitride layer After Ion Millimeter Act as a milling mask as described above for the milling process. Ion milling process Is The exposed portion of the chrome silicon layer 16 is removed, Exposed by it, Stre Excluding portions of the second composite ferromagnetic thin film layer formed as Leave The portion of the intermediate nonmagnetic layer 14 exposed thereby is removed, Thereby dew Of the first composite ferromagnetic thin film layers formed as the extracted stratums 13 and 12 The portion is removed up to the silicon nitride layer 11.   The resulting current sensor and interconnect structure 17 2D hand, It is illustrated as a single layer structure instead of a multilayer structure. Because In these figures, Yo This is because a larger scale is used. Therefore, The obtained current sensor and The interconnect structure 17 This single layer format is shown in both FIGS. 2B and 2C. Part of this structure is Also seen in the plan views of FIGS. 1A and 1B, Also in these figures The reference numeral 17 is attached to the structure of. Easy axis of the ferromagnetic thin film composite layer ) Perpendicular to the direction in which the longest segment of the current sensor in structure 17 extends You.   Following the completion of the current sensor and interconnect structure 17, Silicon nitride 10, 0 An insulating layer 20 having a thickness of not less than 00 ° is formed by sputter deposition (FIG. 2A, FIG. 2B, FIG. 2C and FIG. And in FIG. 2E, Silicon nitride milling shown in combination with this insulating layer On the structure 17 and on the exposed portion of the silicon nitride layer 11 Can be The quality and thickness of the insulating layer 20 is very important. Because Further below As explained in detail, The quality and thickness of the insulating layer 20 are To carry signal current An input conductor provided on the Between the voltage appearing on the current sensor and the interconnect structure 17 This is because the withstand voltage performance of this layer is determined. Good quality and 10, 000Å The insulating layer 20 having a thickness of Providing a breakdown voltage exceeding 1000V, Significantly more than this To increase the capability of the insulating layer 20 to withstand a large voltage, Use a thicker layer Can be.   After providing this insulating layer, Two separate etchings are performed on layer 20 . In the first time, Pattern the entire photoresist, This allows Structure If an opening is to be provided in the insulating layer 20 to form an electrical interconnection with the structure 17 An opening is provided at the place. Opening 21 in layer 20 by reactive ion etching Provided, This allows Exposing layer 16 of structure 17 as shown in FIG. 2C. Second time In the etching step, again, Monolithic forming the semiconductor chip 10 Circuits connected to pads 23 in an integrated circuit provide current sensors and interconnects. To connect the structure 17, In the insulating layer 20, Insulating layer 11 and semiconductor chip base In any other layer in the board 10 Opening required to expose interconnect pads 23 In the place where the mouth 22 is formed, Photoresist provided in a pattern with openings Is done. A portion of pad 23 is shown in FIG. The rest of the interconnect circuit and The electronic circuit electrically connected thereto is not shown.   When these openings in insulator 20 are completed, The first layer 24 of metal interconnect , Initially, the spatula is removed to remove about half the thickness of the exposed portion of the chromium silicon layer 16. Tutter cleaning is provided. Following this wash, Aluminum alloyed with 2% copper Sputter-deposit a layer of film. This layer The openings 21 and 22 are filled. If not, This layer Supported on the upper surface of insulating layer 20. Layer 24 is Open Filling into the mouth 21 leads to the "sandwich" structure of structure 17 Electrical connection, Through the chrome silicon layer 16 and the rest of the tantalum layer 15 And conductively connected, Further, by filling the inside of the opening 22, the Is connected to the pad 23. Providing a photoresist on layer 24; Unnecessary part of layer 24 Pattern so as to be exposed. This unnecessary part, later, Reactive ion etch Removed by This allows Obtain desired interconnect structure in first metal layer 24 You.   By removing unwanted portions of layer 24, Several structures are obtained. That The most important structure is Most of the input conductor through which the signal current flows. This major portion is In the form of a six turn coil 25 And In FIG. 1A, it is illustrated as a hexagonal path. Part of the coil 25, FIG. B, 2A and 2B, The same reference numerals are given. Coil interconnect Minute 25 ' Formed of the same first layer interconnect metal; Coil in FIG. 1A Extending from the right side of 25 to the external interconnect pad configuration 26. This coil interconnect Part 25 ' As explained further below, A second interconnect layer metal portion is provided above. Including a first layer interconnect metal base. The other end of the coil 25 also Less than As explained further below, Connected to interconnect pad configuration 27. Furthermore, Mutual connection Connection paths 28 and 29 As also illustrated in FIG. 1A, Current sensors and interconnects Extending from the end of the interconnect extension of interconnect 17 to interconnect pads 30 and 31 Violated. The interconnect path 28 also The same reference numerals are given in FIG. 2E.   The first metal interconnect layer 24 Typically deposited to a thickness of 5000 to 7500mm And This allows Some parts of the resulting conductive structure Excessive heating or electrons Without migration (electromigration), Maximum in current conductors carrying signal current Ensure that a current density of 5 mA / μm is acceptable. If necessary, Money, copper , Alternatively, an alternative metal such as tungsten may be used for the first layer of the interconnect. Another As an alternative to The number of turns of the coil 25, And Thickness of conductor forming coil And both the width and Impedance given to input current source by coil 25 May be affected. For impedance adjustment, Manufacturing additional circuit structures May be.   Upon completion of coil 25 and interconnect paths 28 and 29, Followed by Above that and above the exposed portions of layer 20, Another 7500% silicon nitride Deposit a layer of concrete, An additional insulating layer 35 is formed. Pattern the photoresist with the opening Learning A hole is provided in the layer 35 under the opening is patterned, and Accepts the interconnect formed by the second layer of interconnect metal as described in Sea urchin Deposited on layer 35, . Using reactive ion etching, These openings Part 36, As shown in FIGS. 2A and 2E, Formed in layer 35.   On the second insulating layer 35, Forming additional metal deposits, Again 2% copper and alloy Forming a second metal interconnect layer 37 of patterned aluminum; This allows Layer 3 Cover 5 The opening 36 is filled. By filling the opening 36 with the metal layer 37, And As shown in FIGS. 2A and 2E, Layer 37 is Formed from the rest of layer 24 Connected directly to the exposed part of the structure. Layer 37 is Typically, 3500mm thick Is deposited. Photoresist having openings at locations where unnecessary portions of layer 37 are removed Strikes on it, Therefore, reactive ion etching is performed to Remove the minute. The structure obtained by this removal is shown in FIG. 1A. This structure Re A lead-out 38. This readout 38 Seen in FIG. 2A like, From the inner end of the coil 25 to the upper part of the insulating rest 35, Therefore, the upper part of the coil 25 And extends to the pad 27. The remaining part of the second metal layer 37 As shown in FIG. Like A pad 26 for transferring signals from the remainder of the first metal layer 24; 30 And 31 to form the metal foundation 39. In FIG. 1A, Broken line Is It does not indicate which layer covers which layer.   By sputter depositing 7500 ° silicon nitride, Further insulating layer 4 0 is provided on the remaining part of the metal layer 37 and on the exposed part of the insulating layer 35. Insulating layer 40 is Acts as a passivation and protection layer for the underlying device structure , Also, It also acts as the basis for a permeable mass. This transmission Sexual lump, Above the current sensor portion of the current sensor and interconnect structure 17 On the part of the coil 25, Flux shield and concentrator Provided to act as.   The configuration of such a concentrator is Ferromagnetic thin film initiation layer It starts by depositing 41. This layer 41 Electrodes for later electroplating process As and, Adhesion for adhering the next layer of metal provided thereon to the insulating layer 40 Acts as a layer. Then Deposit and pattern the photoresist, this By Layer above current sensor portion of current sensor and interconnect structure 17 An opening is provided on the portion 41. Then 20 gold in this opening, 000Å Electroplate. this is, A stress relief layer of a mass of permeable material that is later deposited there (stress relief layer) 42. Then After depositing the starting layer Remove the coated photoresist layer, A new opening is defined above the stress relief layer 42. Apply a new photoresist. Then The permeable mass 43 This last opening The inside is formed by electroplating. This mass is 80% iron and 20% nickel Formed from an alloy of permeable materials, including: Deposited to a thickness of 14 microns.   Then The photoresist that guides the plating of layer 43 is removed. Equipment Re Acid, Acetic acid, Immersed in an acid bath formed from a mixture of and nitric acid, This allows The starting layer 41 is removed from portions other than below the layers 42 and 43. The resulting permeable mass Body shield and concentrator, Illustrated in FIG. 2B. Then Interconnect Pad 26, 27, On 30 and 31 A via opening 44 is provided in the layer 40. A further layer of photoresist having openings at the locations where Deposits on equipment. Anti Using reactive ion etching, An opening is provided as seen in FIG. 2E. this These openings are External circuit through the base 39, usually by ball bonding wiring Enables the next interconnection to afterwards, The wafer forming the above apparatus is Ue C inspection, Preparing the separation of individual devices into separate chips and their packaging Ready state.   FIG. 1A, FIG. 1B, FIG. 2A, FIG. 2B, FIG. 2C, 2D and 2E. One of the basic modes of operation of the isolator device is: Current sensor and interconnect structure While supplying a constant current via 17 A mode that monitors the voltage developed across the structure Is. This voltage is Due to the magnetoresistance of structure 17, Conducted through coil 25 It is a function of the magnitude of the incoming signal current. Therefore, The measurement voltage is At least enough For the current in the coil 25 having a small frequency content, Current sensor The electrical resistance of the interconnect and interconnect structure 17; And the magnitude of the current flowing through the coil 25 It is an index.   The resistance measured for structure 17 is About the zero signal current in the coil 25, It turns out to be symmetrical, Both positive and negative currents through the same size coil Are almost equivalent to each other. But, The resistance of structure 17 is As can be seen in FIG. It must be a non-linear function of the magnitude of the signal current in coil 25. I understand. This nonlinearity is Structural configuration of the device described in these figures, Forming a current sensor in a current center in interconnect structure 17 Magnetic properties of the "sandwich" structure, And shields and concentrators This is considered to be due to the magnetic properties of the material in the data layer 43. Furthermore, In coil 25 For sufficiently large signal currents, Heat effect, Current sensor and interconnection structure 1 7 affect the resistance. Because The thermal coefficient of the structure is Typically about 1400pp This is because m / ° C. Typically, Frequency at which the operation of the device is not affected by frequency The number range is Up to tens or hundreds of megahertz.   FIG. 1A, FIG. 1B, FIG. 2A, FIG. 2B, FIG. 2C, FIG. 2D, And in FIG. 2E The output for the current flowing in the coil 25 indicated by the signal isolator as described above is , The accuracy is limited by the nonlinearity described above. This performance limitation is Entering Using two or more signal isolators in the power circuit, The added isolator is Helping to counteract the effects of nonlinearities exhibited by the first isolators. By making it possible, it can be substantially reduced. Such input to achieve this result One of the power circuits is This is to use the input-output current tracker 50 shown in FIG.   The current tracker 50 is A first terminal 51 suitable for connection to a source of a stop voltage; negative It operates between a further terminal 52 suitable for connection to a voltage supply. Another terminal 5 3 is Connected to provide reference voltage or ground reference voltage. This criterion A voltage is supplied to terminals 51 and 52 with respect to a voltage or a ground reference voltage.   The tracker 50 A pair corresponding to the interconnect pad configurations 26 and 27 of FIG. 1A. Input terminals. In FIG. 4, these reference numerals are used for these input terminals. I have. Similarly, The coil 25 of FIG. 1A is interconnected between terminals 26 and 27, Figure 4 is also given the reference numeral 25. The coil interconnect 25 'of FIG. And coil readout 38 Reference numerals for equivalent conductor parts shown in FIG. . Finally, The current sensor and interconnect structure 17 of FIGS. 1A and 1B include: In FIG. References are made as for equivalent resistors. Coil 25 and current sensor and mutual Both connection structures 17 are shown within the dashed box 54, This allows These are both magnetoresistive 4 illustrates forming an effect-type current sensor configuration.   The remaining part of the current tracker 50 of FIG. Configuration of magnetoresistive current sensor 54 Additional magnetoresistive current sensor intended to be manufactured to conformity Starting with the addition of 55, It differs from that shown in FIGS. 1A and 1B. As a result, Within the dashed square representing the magnetoresistive effect type current sensor 55, Sensor 5 5 is 17 ′, The coil member is 25 ″.   Each of the magnetoresistive members 17 and 17 'of the sensors 54 and 55 has Set During operation with the corresponding constant current source of the current source pairs 56 and 57, Constant current supply Is done. These constant current sources are The current supplied by one is exactly the current supplied by the other To match It is intended to be manufactured to conform structurally to one another. The current source 56 is connected between the terminal 51 and the magnetoresistive member 17, The current source 57 is a terminal 51 and the magnetoresistive member 17 '. Magnetic resistance members 17 and 1 Each of 7 ' The opposite end is connected to terminal 52, This allows Half brid A circuit is formed. Each bridge circuit member is supplied with current by the corresponding constant current source And The resistance value of each member is Changes due to the current flowing through the adjacent coil You.   The differential input of the operational amplifier 58 is Respectively, For current sources and magnetoresistive members Connected to one corresponding joint. Therefore, The inverting input of the operational amplifier 58 is Electric It is connected to the junction between the flow source 56 and the magnetoresistive member 17. Non-inverting of operational amplifier 58 The transfer input is The current source 57 and a magnetoresistive resistive member (magnetoresistive resistive member) member) 17 '. The output of the operational amplifier 58 is Diode 5 9 and to the output 60 of the current tracker 50. further, Calculation increase The width device 58 is Connect to both terminals 51 and 52 of the corresponding positive and negative voltage supply terminals. Continued. The operational amplifier 58 As a transconductance amplifier, Fig. 4 times Operate in the road, Differential input, Single output, High gain, High input impedance , It is a low output impedance amplifier.   The cathode of the diode 59 is Connected to the coil member 25 ″ of the sensor 55 . The opposite side of the coil member 25 '' Connected to ground terminal 53. diode 59 is The current passing through the coil member 25 " So that this current flows into the ground To And used to restrict the flow from ground through the coil Is done. this is, Magnetoresistive members 17 and 17 for current in adjacent coils 'By the symmetry in the resistance characteristics. This symmetry is Input coil member Regardless of the current in only one direction out of 17, Which current passes through the coil member 25 '' Flow in the direction of Noise pulses can be created that force the circuit into a stable state.   Input current sensed and tracked by current tracker 50 Is Supplied to the input terminal 26 of the tracker 50, as a result, Coil 2 of sensor 54 A current exiting terminal 27 through 5 is established. Such a current That week Create a magnetic field in the enclosure, Similarly, a magnetic field is formed around the magnetoresistive member 17 of the sensor 54. And This allows The resistance is effectively changed. Due to such a change in resistance, hand, A change occurs in the voltage present at the junction of member 17 and current source 56, This And The voltage developed at the junction between member 17 and current source 56; Magnetic resistance member 17 ′ And the voltage at the junction between the current sources 57.   This potential difference is at the same time, Transconductance amplifier, Or voltage-current Also occurs between the differential inputs of the operational amplifier 58 acting as an inverter, Therefore, Increase Amplified by the breadth, From there, the coil member 25 ″ is passed through the diode 59. Supply the corresponding output current into the interior. Such a current Introduced at terminal 26 Differential between the input terminals of the operational amplifier 58 due to the applied input current In the direction that tends to zero voltage, Of the member 17 ′ based on the magnetoresistance effect This causes a change in resistance.   Each magnetoresistive member 17 and 17 'in sensors 54 and 55 Good one with each other It is manufactured to match as a result, Part caused by current in coil 25 '' The change in the resistance of the material 17 ′ Due to the input current introduced in the coil 25 It is intended to be exactly equal to the change that occurs in the material 17. Therefore, This By balancing the resistance change as in Supplied to the coil 25 '' If the current at its output is exactly equal to that introduced through terminal 26, Performance No significant potential difference should remain between the differential input terminals of the operational amplifier 58. Obedience What At the output of the operational amplifier 58, an output current is supplied to the coil 25 ''. , This current is Magnetic resistance members 17 and 17 'are connected to coil members 25 and 25'. Despite not necessary necessary linear functions of the flowing current Without It will be substantially equal to the current established through terminal 26. In these cases And The output voltage of the operational amplifier 58 supplied to the output terminal 60 is To input terminal 26 It is one of the measures of the flowing current.   But, The desired result of this matched input and output current is Sensor Strictness of coincidence of the characteristics of the magnetoresistive members 17 and 17 'of 54 and 55, and It depends on the exactness of the matching of the currents supplied by the current sources 56 and 57. That If the members 17 and 17 'match well including the non-linearity phase, Magnetic resistance part The response of the members 17 and 17 'to the current in the coils 25 and 25' The existence of linearity means that While not changing this desired result, If the match is not good In Such non-linearities can have less desirable consequences.   This means Amplify the output current in coil 25 '' at the input of amplifier 58 Can be found by setting equal to the given potential difference, Current tracker It can be seen from the equations characterizing the 50 behaviors. This potential difference is Magnetic resistance member 17 And 17 ', The current supplied by the current sources 56 and 57 and the input current Is determined by the value of the resistance characteristic equation.In this equation, I_outIs established at its output through coil 25 '' The output current of the amplifier 58_inIs supplied to the terminal 26 and passes through the coil 25. Represents the input current passed. Current I₅₆And I₅₇Are the corresponding current sources 56 and And 57 are the currents established. The gain constant G is equal to that of the operational amplifier 58. Represents the transconductance between the output and the differential input.   Each of the magnetoresistive members 17 and 17 ′ in the above equation Non-linear resistance up to second order for current in corresponding coils 25 and 25 '' Modeled as a vessel. The equations for these models are It is. That is, the magnetoresistive members 17 and 17 'are 'Senses currents with non-linear resistors in power series up to the second order of these currents. Modeled. The coefficients in these equations are R 17K₀And R17'K₀, And for the first power, R17K₁And R 17'K₁And the squares are R17K respectively_TwoAnd R17'K_TwoIs . Members 17 and 17 'using second-order polynomial regression The best fit for the characteristics shown in FIG. 3 for such a magnetoresistive member is The following equations are given for these magnetoresistive members.   The sensed input current I supplied to terminal 26 and passing through coil 25_inAnd circuit components Output of amplifier 58 with respect to product parameters and circuit parameters based on topology. Provided through coil 25 '' from_outSolving this equation for Can be. Assuming G is large enough, the result is:The value of the resistance characteristic coefficient of the magnetoresistive member is obtained from the above-described quadratic optimal fitting equation. be able to. Then, by selecting the current values from current sources 56 and 57, What I_outThe above equation for_inCan be evaluated against the value of   I as such a function_outImmediately by the evaluation of I_inVarious values of I_outAnd I_inThe degree of coincidence is the parameter of the magnetoresistive members 17 and 17 '. It can be seen that it largely depends on the quality of data matching. Coils 25 and 25 '' No current is applied to the magnetoresistive members 17 and 17 ′ in the state where no current is supplied to them (nom). inal resistance values), that is, R17K₀And R17 'K₀If there is a mismatch in the values of_outIn the radical in the last expression about I as considered by the second term_outAnd I_inThere is a significant difference between them. This Is that the third term in the radical is I_in, The size of the second term is relatively small It stays there until it gets big enough. Therefore, members 17 and 1 7 'when there is a mismatch in the nominal resistance_inIs relatively small, I_{ou t} And I_inThe agreement between them is relatively poor. I_inIs large enough, I_out And I_inThe agreement between them improves surprisingly.   I_outAs seen in the third term in the radical in the last equation for , The coefficient R1 of the quadratic term in the quadratic notation for the magnetoresistive members 17 and 17 ' 7K_TwoAnd R17'K_TwoBy exactly matching_outAnd I_inwhile The match is further improved. In these secondary notations for these magnetoresistive members, Coefficient R17'K for the first order term₁But the quadratic terms in these notations If it is much smaller than the coefficient, the match is further improved.   In the current tracker 50, each of the magnetoresistive members 17 and Importance of matching between resistance characteristics as a function of adjacent coil current for Consideration should be given to ensuring a good match between these properties or Great effort may be required to counteract the effects of the disagreement. Match the above One of the standard ways to improve is to use well-known resistor trimming techniques after manufacture. Therefore, the resistance of one of these magnetoresistive members is adjusted to more strictly the other. The goal is to match. Another possibility is that during operation, the power in the circuit of FIG. The locations of the sources are swapped frequently enough to eliminate inconsistencies in the current sources. The results obtained in each of the above cases when providing the circuit output to overcome Effective averaging of the results. Current sources 56 and 57 and magnetic resistance section Analog transfer that can be integrated in the same monolithic integrated circuit as materials 17 and 17 ' Using complementary metal oxide semiconductor field effect transistors as gates Therefore, such replacement can be performed.   One further possibility is that a filter such as that used in the circuit shown in FIG. A bridge circuit. Here, the current sources 56 and 57 in FIG. Instead, two additional magnetoresistive current sensor configurations 56 'and 57' are used. Of course, it also supplies current to the sensors 54 and 55. Terminal 26 5 is supplied to the magnetoresistive member 17 and the magnetic resistor. The current output from the amplifier 58 passes through both of the resistance members 17 '' ' 7 '' and the magnetoresistive member 17 ''. Thus two further The magnetoresistive members 17 "and 17" "are connected to sensors 56" and 57 ", respectively. To increase the computation for the input current supplied to terminal 26. The signal voltage at the input of the breadther 58 is doubled. This increase is due to the failure of the magnetoresistive member. Reduce any offset current due to the match, and thus reduce Improved linearity to operate with a more closely matched current due to offset I do.   One of the possible layouts in a monolithic integrated circuit chip for the circuit of FIG. On an electronic circuit formed in a semiconductor material substrate, also in a chip. Figure 6 shows the magnetic interacting portions of the circuit Shown in These electronic circuit parts of the above circuit are mounted on the substrate within the dashed square shown in FIG. Included to minimize interaction with the input current. Corresponding circuit in the circuit of FIG. The same reference numerals used for the members are used for the components in FIG. These components Is substantially the same as that used for the members shown in FIGS.   Although the present invention has been described with reference to the preferred embodiments, those skilled in the art will recognize Format and details can be changed without departing from the spirit and scope of the Will recognize.

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Claims (1)

[Claims] 1. At the output, a power supply providing an indication of the input current supplied from a source of the input current. A flow determiner,   Board and   An input conductor supported on the substrate, suitable for conducting the input current;   A first current sensor supported on the substrate, adjacent to the input conductor; Is spaced from the input conductor so that the input conductor Is electrically isolated from any direct circuit interconnects, Are located in the magnetic field generated by them, are magnetoresistive, anisotropic and ferromagnetic Formed from a plurality of thin film layers, at least two of the plurality of thin film layers being between them. A first current sensor, separated from each other by an underlying non-magnetic layer, And a current determiner. 2. A magnetic field capacitor located near both the input conductor and the first current sensor. The contractor further comprising a layer of substantially magnetically permeable material that acts as a centrator. An apparatus according to claim 1. 3. The first current sensor has a major extension along a first direction on the substrate. A second direction on the substrate, wherein the input conductor is substantially orthogonal to the first direction. 2. The device of claim 1, having a major extension along. 4. The substrate further includes a monolithic integrated circuit structure including electrical circuit components; At least one of the electrical circuit components is electrically connected to the first current sensor The apparatus of claim 1, wherein 5. A second current sensor supported on the substrate, the second current sensor on the substrate; On the substrate so that it is electrically isolated from any direct circuit interconnects with the sensor. A second adjacent, but spaced from, another supported conductor; Further comprising a current sensor, wherein the second current sensor occurs at the another conductor. The second current sensor is located in a magnetic field generated from the current, and the second current sensor is a magnetoresistive The thin film layer is formed of a plurality of anisotropic and ferromagnetic thin film layers. The device of claim 1, wherein at least two are separated from each other by a non-magnetic layer. 6. A layer of substantially magnetically permeable material oriented substantially parallel to the substrate Wherein both the input conductor and the first current sensor are at least Partially located between the magnetically permeable material layer and the substrate, the magnetically permeable material layer is 5. The device according to claim 4, acting as a concentrator. 7. Each of the first and second current sensors are connected to each other and the first and second current sensors. Claims that can be electrically connected to and supply current to a corresponding one of the current sources. Item 6. The apparatus according to Item 5. 8. Each of the first and second current sensors is connected to each other and to a third and fourth current sensor. The third and fourth current sensors are electrically connected to corresponding ones of the current sensors. Each sensor is formed from multiple thin layers of magnetoresistive, anisotropic, and ferromagnetic And at least two of the plurality of thin film layers are formed by a nonmagnetic layer located therebetween. And the fourth current sensor is electrically connected to the third current sensor. Wherein the first and third current sensors are connected in series with each other via an electrical energy application source. And the second and fourth current sensors are electrically connected to an electrical energy application source. Are electrically connected to each other in series through a third circuit to form a bridge circuit. A sensor is supported on the substrate and is adjacent to but spaced from the input conductor. Is electrically isolated from the input conductor by opening the Located in a magnetic field generated from the current, the fourth current sensor supported on the substrate Shall be adjacent to, but spaced from, the other input conductor. Is electrically isolated from the other conductor by the 6. The device of claim 5, wherein the device is located in a magnetic field generated from an electric current. 9. Having an output and a pair of inputs, wherein a potential difference occurring between the two A differential amplifier for providing an amplified indication, wherein the amplifier inputs are each A corresponding one of the first and second current sensors and the first and second current sensors. 8. The electrical connection to a connection between a corresponding one of the sources. An apparatus according to claim 1. 10. An output and a pair of inputs, wherein a potential difference occurring therebetween appears at the output. Further comprising a differential amplifier, which is an amplified representation of one of the amplifier inputs. Is electrically connected to a connection between the first and third current sensors, and The other of the forces is electrically connected to a connection between the second and fourth current sensors. The device of claim 8, wherein 11. The differential amplifier output is electrically connected to the another conductor. Device according to claim 9. 12. The differential amplifier output is electrically connected to the another conductor. An apparatus according to claim 10. 13. Provide an output current whose magnitude is substantially in accordance with the magnitude of the input current supplied to the input. A current tracker for supplying   A bridge circuit electrically connected to an electrical energy application source, wherein the bridge circuit is The circuit includes a plurality of magnetoresistive members, each of the plurality of magnetoresistive members being magnetic. A resistive current sensor having a plurality of sensing conductors, each of the plurality of sensing conductors Are adjacent to the corresponding magnetoresistive member, and the magnetoresistive member is electrically connected to the input. And electrically isolated from any direct electrical interconnection with the bridge circuit A further sensing conductor including the sensing conductor and adjacent to the corresponding magnetoresistive member; A bridge circuit without any magnetically permeable material in between,   A plurality of inputs electrically connected to the bridge circuit; and A differential input amplifier having an output connected in series and providing the output current; A current tracker. 14． 14. The bridge circuit of claim 13, wherein the bridge circuit further comprises a plurality of current sources. Equipment. 15. The bridge circuit includes at least four of the plurality of current sensors. 14. The device according to claim 13, comprising a current sensor based on a magnetoresistive effect. 16. A second current sensor supported on the substrate, adjacent to the input conductor; But is spaced from the input conductor, so that Is electrically isolated from any direct circuit interconnection with the input conductor A second current located in a magnetic field emanating from the current occurring in the input conductor Further comprising a sensor, wherein the second current sensor is magnetoresistive, anisotropic, and ferromagnetic. Formed from a plurality of thin film layers that are conductive, at least two of the plurality of thin film layers being The device of claim 1, wherein the device is separated from each other by a non-magnetic layer located therebetween. . 17． The first current sensor is at least partially electrically connected to the input conductor. The device of claim 1, wherein the device is spaced by an insulating material. 18. The input conductor supported on the substrate is formed as a coil, The coil is about a point inside the coil and the interior is substantially orthogonal to the coil; The device of claim 1, wherein the device does not extend substantially along an axis passing through the point. 19. The input conductor supported on the substrate is formed as a coil, The coil is about a point inside the coil and the interior is substantially orthogonal to the coil; 3. The device of claim 2, wherein the device does not extend substantially along an axis passing through the point. 20. Before the differential amplifier output and the output current provided by the differential amplifier 14. The method of claim 13, wherein there is a diode electrically connected to the sensing conductor. apparatus. 21. The electrically insulating material is disposed between the input conductor and the first current sensor. 18. The apparatus of claim 17, wherein the thickness is at least 10,000 degrees. 22. Provide an output current whose magnitude is substantially in accordance with the magnitude of the input current supplied to the input. A current tracker to provide,   A bridge circuit electrically connected to an electrical energy application source, wherein the bridge circuit is The circuit includes a plurality of magnetoresistive members supported on a substrate, the plurality of magnetoresistive Each of the conductive members is a magnetoresistive effect type current sensor, and a plurality of A sensing conductor, wherein each of the plurality of sensing conductors is adjacent to a corresponding one of the magnetoresistive members. Wherein the magnetoresistive material is electrically connected to the input and the bridge circuit on the substrate Including said sensing conductor electrically isolated from any direct electrical interconnection with A bridge circuit, wherein there is further the sensing conductor adjacent the corresponding magnetoresistive member;   A plurality of inputs electrically connected to the bridge circuit; and A differential input amplifier having an output connected in series and providing the output current; And a current tracker. 23. 23. The bridge circuit of claim 22, wherein the bridge circuit further comprises a plurality of current sources. Equipment. 24. The bridge circuit includes at least four of the plurality of current sensors. 23. The device of claim 22, comprising a current sensor based on a magnetoresistive effect. 25. The differential amplifier output and the sense amplifier with the output current from the differential amplifier. 23. The device of claim 22, wherein there is a diode electrically connected to the known conductor. .